People come to your blog out of choice and not any compulsion. If you remember this, the rest is not important enough.
Acknowledge and appreciate your readers, especially regular readers by replying to comments and visiting their blogs.
Grammar - Depending on the language you use, blogging just makes it imperative that you are reasonably good with your grammar skills and proficiency if not a master. Remember your audience is a mix of both; the ones who are experts and the ones who are not.